Selective charge-firing equipment



SELECTIVE CHARGE FIRING EQUIPMENT iled oct. 25, 1948 2 Sheets-Sheet 1 ATTORNEYS Oct. 13, 1953 w. E, NEAL 2,655,619

SELECT IVE CHARGEFIRING EQUIPMENT Filed Oct. 25, 1948 v 2 Sheets-Sheet 2 43 47 4-6 n/45 6 40 J 1 6/ j 42 43 a 34 4 Fig. 4

' WilliamENd/ Fig. 3 3% fl ATTORNEYS.

Patented Oct. 13, 1953 SELECTIVE CHARGE-FIRING EQUIPMENT William E. Neal, Houston, Tex., assignor, by decree of court, of one-half to Cherrietta Dover Application October 25, 1948, Serial No. 56,368

2 Claims.

This invention relates to a selective chargefiring equipment which can be lowered into well bores, as cased oil wells, after which charges within the gun may be ignited to be self-propelled into contact with the casing to burn holes therethrough.

It is an object of this invention to provide a gun perforator in which the perforating charges therein may be fired one after the other in sequence by an electrical current.

It is also an object of this invention to provide the gun perforator of this class in which the charges may be ignited one after the other by the re-setting of a relay switch and the pushing of a control switch each time after a charge has been ignited.

It i a further object of this invention to provide a gun perforator of this class in which the chambers containing the charges are maintained under higher pressure than exits in the casing or bore surrounding the perforator.

It is yet another object of this invention to provide a gun perforator of this class from which the charges may be self-propelled with great velocity from one chamber without setting off charges in chambers proximate thereto.

It is still another object of thi invention to provide a gun perforator of this type in which the order of firing the charges depends upon the electrical wiring thereof, and not upon their relative locations within the gun.

It is yet another object of this invention to provide a gun perforator of this class in which the chambers containing the charges are maintained at substantially the pressure which exists in the casing or well bore surrounding the perforator.

Other and further objects of thi invention will be apparent when the specification is considered in connection with the drawings, in which:

Fig. 1 is a sectional elevation of the lower section of the gun perforator;

Fig. 2 is a sectional plan view through one of the chambers of the lower section of the gun perforator taken along line 2-2 of Fig. 1;

Fig. 3 is a sectional elevation of the upper section of the gun perforator;

Fig. 4 is an electrical diagram of one form of firing circuit employed;

Fig. 5 is an electrical diagram of another type of firing circuit employed;

Fig. 6 is a plan view of the contactor disc and firing arm taken along line 6-5 of Fig. 3, the portion of the gun above the disc being omitted.

The lower section I of the gun perforator has a rounded bottom 2. The portion thereabove is subdivided into chambers 3 by the walls 4, which extend transversely across the section. Charges 5 are mounted in the walls between base receptacle 5, which receives the head I of the charges, and the cylindrical insert 3,-which receives the end portion 9 of the body of the charge, which is some bit larger in diameter than the head I. The cylindrical insert 8 is threaded and counterbored to form a seat for the diaphragm Ill, which is preferably made of strong metal of light gauge. This diaphragm is held in place by means of the bushing II. which is threaded into the insert 8. the insert in turn being positioned in holes I2 in the section wall and welded to the section.

The internal cross-sectional areas of the bushings I I and of the inserts 8, are sufliciently large, with relation to the charges 5 to permit the escape from the chambers of the gases of explosion generated upon detonation of the charges, thereby avoiding the building up of excessive pressures within the chambers before the gases may be liberated therefrom.

Air valves I3 are installed in the wall of the section so that compressed air may be passed therethrough to build up a pressure within the chamber which is sufiiciently great to counterbalance well bore pressures externally thereof which might otherwise tend to cave in the chamber walls, or cause fluid leakage therethrough. Although not shown in the drawings, air valves I3 may be inserted in the walls of the gun perforator to permit all or part of the interior space above the upper chamber 3, the space within the conduit I I, and the rounded bottom chamber to be maintained at substantially the pressure of the chambers.

Conduit I4 extends from the lowest transverse wall 1 up through the top transverse wall 4 and is welded to each wall by an air tight weld. Insulated wires I8 from the firing circuit, to be described hereinbelow, are led down the conduit and one of such wires passes out through an air tight insulator 31 into each chamber 3 to be connected to a cap I5 which is fixed to the fuse I6, the fuse in turn being passed through the head I of the charge 5. A second wire I'I grounds the cap I5 to the wall of the section.

The lower section I is threaded and counterbored to form a seat 20 for the contactor disc 2| which has radially spaced near the circumference thereof the metallic contactors 22 to which are fixed the wires I8 for carrying current therethrough. This contactor disc 2| is of a strong but insulative material and is centrally bored to- 3 receive the bushing 23 into which may be fitted the shaft 24 which is driven through the speed reducer 51 by the motor 25.

The motor 25 i mounted in a mounting tube 26 of a diameter to permit it to be seated near the periphery of the disc 2| and within the coupling 21 which is threaded into the lower section I to firmly seat the disc 2| against the seat 20. The head 28 is threadable upon the upper end of the coupling 21 to seat against the top of the mounting tube 26 to firmly restrain it between head and disc.

A firing arm 29 is mounted on the-shaft 24 and is insulated from the shaft by the bushing 36. This arm 29 is of a length so that the firing tip 32 thereof may engage the contactors 22. A brush 3| is positioned within the mounting tube 26 by means not shown, to be contacted by the flange 33 of the arm 29.

The brush 3| is connected to the wire 34 which extends up through the insulator bushing 35 in the head 28, the connector 36, the insulator bushing 38 of the top plug 40, and on through the insulative layer 4| to the battery terminal 42 at thetop of the well.

As shown in Fig. 4, the circuit is completed by a line which extends from the terminal 43 of the battery 44 to the ammeter 45, from there to the push button 45, and on through wire 41 to the metallic sheath 48v which surrounds the insulative layer 4| and which is grounded by means of, flared end 63 to the, top plug 40.

Within the mounting tube 26, the wire 55. is spliced to the wire 34, and. is connected to one terminal of the motor 25. The ground wire 5| then interconnects the other motor terminal and the mounting tube 26. The motor 25 has the normal resistance encountered in conventional motors of less horse power, and a resistor 52 is inserted in the line 34 between brush 3| and the point of connection with wire 5|], to insure a proper distribution of current between motor circuit and firing circuit.

As shown in Fig. 5, another circuit may be employed which connects wires 34 and 41 to brush 24 and sheath 48, respectively, as hereinabove described for the circuit shown in Fig. 4, but this circuit additionally has a normally closed overload circuit breaker or relay 53 included therein between battery 44 and ammeter 45.

In operation the perforator gun, employing the circuit of Fig. 4, is suspended from the cable to some point within a well bore at which it is desirable to perforate the casing in order to permit fluids around the exterior thereof, such as oil, to flow Within the well bore. Then the operator at the top of the well closes a switch or push button. 46, with the result that current flows through the circuit of the motor 25 and also through the parallel circuit through the brush 3| and firing arm 29 to the contactors of the contactor, disc 2|.

Several of these contactors, preferably three, are grounded by means of wires, 54 to the lower section At outset the firing arm 29 is set with the firing tip 32 on the starting contactor 55 which is connected by one of the ground wires 54 to the lower section I. The current flowing through the wire 59 actuates the motor to rotate the firingarm 29 to the next contactor 56. Upon the establishment of surface contact between the firing tip 32 and this contactor, current also flows through these contacting surfaces and through the ground wire 54.

The, operator at the top of the well observes when the tip 32 has been rotated over to contact the next contactor 56 the needle jumps up again to indicate the higher current flowing in the line. The contactor 51 may also be wired, as is the contactor 5'6, for use as a check point.

When the firing tip 32 is further rotated into contact with the contactor 58, current flows through the brush 3|, firing arm 29, firing tip 32, contactor 5B, and wire |8 to ignite the cap |5. The ignition of the cap carries through to the fuse l6 and onto the head I of the charge 5 to ignite the charge, as will be hereinafter described.

When the push button 46 is first closed, the ammeter needle jumps up to indicate the current flowing in the wire I6, but the resulting prompt ignition of the cap |5 breaks the firing current,

so that the needle falls away, almost as suddenly as it has first jumped up, to indicate the near-zero reading of the current which flows through the motor. This sudden falling off of the ammeter needle froma higher reading offers a visual comparison with the much longer maintained higher reading during the interval it takes the firing tip 32 to traverse any or the grounded contactors 55, 56, and 51, and thus the operator knows when. a check point is being traversed and when a charge is being fired.

As long as the operator keeps his finger on the push button 46 the motor will rotate and continue bringing the firing tip 32 into contact with successive contactors until all the charges in the gun perforator have been fired.

When the circuit of Fig. 5, containing the overload circuit breaker 53, is employed at the top of the well, the change of current flowing in the circuit breaker. coil '64 when the firing circuit is broken results in an induced voltage of sufiicient force to move the circuit breaker shaft 59 to the right to break the contacts of points 66 and 6|, with the line terminals 62 and 63 with the result that the flow of current to the gun perforator is broken.

This immediately stops the motor so that the firing tip 32 remains in contact with the contactor for the charge which has just been fired.

To continue the. firing operation it is thus necessary for the operator to reset the circuit breaker 53 by pushing the contacts and BI back into contact with the terminals 62 and 63 every time anew contactor figures in the gun perforator operation. After this has been done, the operator must again press the push button 46 to start the motor.

With this circuit, the overload circuit breaker 53 may be set so as not to break contact when the firing arm 29. breaks or makes contact with successive check point grounded contactors 55, 56 or 51, in which case the ammeter needle will jump up to indicate the traversing of each contactor and fall oil thereafter, as described hereinabove for the circuit of Fig. 4.

Optionally the circuit breaker 53 may be set to kick out responsive to the induced voltage occurring both upon breaking and establishing contact between firing arm and the grounded contactors, and in this case the circuit breaker will have to be re-set twice in order to accon plish the traversal of each grounded contactor. In either case, the employment of the circuit of Fig. 5 gives a distinct visual comparison between the traversal of a check point and the firing of a charge.

The charges 5 employed in this invention are of any Well known type which have therein a propellant and an arrangement of structures so designed that when the ignition of a cap i5 carries on through a fuse 16 to the charge propellant, the detonation of the propellant self-pr0pe1s the charge through the dia hragm ID, and on through casing wall and through any cement exterior thereof, so that fiuid, as oil, may flow through the holes thus created in casing and cement.

It is a feature of this invention that the charges which are fired successively need not be in compartments adjacent to each other but rather the charges may be Wired to be fired in any desired order as regards their relative positions within the gun perforator.

Broadly, this invention considers a gun perforator of this class in which a plurality of charges may be fired in rapid succession but in a manner to permit observation of the indication of the firing of each charge. The invention also considers the firing of successive charges which may be spaced apart in time at the will of the operator by virtue of the inclusion of a normally closed relay in the circuit.

What is claimed is:

1. The combination of a means for selectively firing charges from a remote point comprising an insulative disk, contactors in said disk having grounded connections, other connections completing charge firing circuits from another plurality of contactors, a firing arm to contact the several contactors in succession, an electrical actuator for said firing arm, a brush in wiping engagement with said firing arm, a conductor joined to said brush and said electrical actuator for extension to said point, and an electromotive circuit joined to said conductor at said point and including therein an ammeter and a switch so that upon closing the switch the ammeter will visually differentiate the movement of the electrically actuated firing arm over the grounded contactors and over the charge-firing contactors.

2. The combination of a means for selectively firing charges from a remote point comprising an insulative disk, contactors in said disk, connections for grounding certain of said contactors and other connections for completing chargefiring circuits, a firing arm to contact the several contactors in succession, an electrical actuator for said arm, a brush having wiping contact with said firing arm, a conductor from said brush and said actuator leading to said point, and an electrical circuit at said point connecting with said conductor and including therein an ammeter and a switch so that upon closing the switch the ammeter may visually differentiate the firing arm movement over the grounded contactors and over the charge-firing contactors, and a normally closed relay in said electrical circuit operable to break the circuit responsive to change of rate of current fiow through said circuit so that said relay must be manually closed and said switch manually actuated each time the firin arm is moved from contactor to contactor.

WILLIAM E. NEAL.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,582,18e Mims Apr. 27, 1926 2,948,451 Johnston July 21, 1936 2,252,270 Miller Aug. 21, 1941 2,266,345 Turechek Dec. 16, 1941 2,2795% Miller Mar. 17, 1942 2,317,238 Mennecier Apr. 20, 1943 2,331,058 Stick, Jr. Oct. 5, 1943 2,338,872 Robidoux Jan. 11, 1944 2,369,238 Kayeler et al. Feb. 13, 1945 2,331,991 Schlumberger Aug. 7, 1945 53 128,334 Lubelsky Sept. 30, 194.7 2,481,033 Nelsen Sept. 6, 1949 2,491,255 Muskat et al. Jan. 10, 1950 2,623,922 Muflly Dec. 30, 1952 FOREIGN PATENTS Number Country Date 757,734 France Dec. 30, 1933 

